/*!The Treasure Box Library
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright (C) 2009-present, TBOOX Open Source Group.
 *
 * @author      ruki
 * @file        exp1.c
 * @ingroup     libm
 *
 */

/* //////////////////////////////////////////////////////////////////////////////////////
 * includes
 */
#include "math.h"

/* //////////////////////////////////////////////////////////////////////////////////////
 * implementation
 */
tb_double_t tb_exp1(tb_double_t x)
{
    tb_assert(x >= -1 && x <= 1);
    return (1 + (x) + ((x) * (x)) / 2 + ((x) * (x) * (x)) / 6);
}
